The Research Of Time-delay Stability For Power Systems Based On Free Matrix Integral Inequalities Method

In the increasingly complex modern power system,in order to ensure the stable operation of the power system,it needs real-time monitoring from a global perspective,and the establishment of a wide-area measurement system enables this goal to be realized.However,there is a communication delay in the wide-area measurement system,which is one of the reasons for the instability of the power system.The theoretical research of time-delay systems has attracted a lot of researchers' attention,but these theoretical methods have a large application space in the power system.To verify the validity and applicability of these methods,the power system based on the wide area measurement system provides an application platform.This thesis has done some research on the communication time delay phenomenon in the wide area measurement system.The main work is as follows:(1)The working principle,structural composition and time-delay of the wide-area measurement system in the power system are analyzed in detail,and the types of communication delays are divided.According to its characteristics,a mathematical model of differential algebraic equations with time-delay terms is established,which delays a foundation for the application of the time-delay stability correlation analysis method based on free matrix.(2)A delay stability criterion based on free matrix integral inequality is given,and applied to a single-machine system.Firstly,a LyapunovKrasovskii functional is constructed.When the integral term existing in its derivative is processed,A delay-dependent stability criterion based on free matrix integral inequality is established.It has lower conservation.Mathematical modeling of a single-machine infinite system with timedelay,and derive its system state parameter matrix that affects time-delay.The time-delay stability margin of the system is calculated by the method of free matrix integral inequality proposed in this paper.The superiority of the method is proved by comparison with the literature,and the validity of the result is verified by Simulink simulation.(3)Multi-machine power system modeling and time-delay stability analysis.In order to more accurately simulate the actual power system operation,the multi-machine system is taken as the research object,and the existence of single time delay,multiple time lag,multi-time delay and uncertain parameters are considered.Analysis of time-delay stability by using different time-delay correlation stability analysis methods.The Simulink simulation of multi-machine systems with single time delay and multiple time delays is carried out,and the applicability of the proposed method is verified.Considering the influence of uncertain parameters in the excitation amplification factor of the generator on the stability of the time-delay power system.Applying an integral inequality method with uncertain parameters,the time-delay stability margin is calculated.The numerical results show that the method applied in this paper is effective for evaluating time-delay power systems with uncertainties of various parameters.